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Silent Spring 50th Anniversary Essay Series

50 Years After Silent Spring:

Minnesota’s St. Louis River Showcases Environmental Success and Challenge

While providing unparalleled scenic beauty and significant fish and wildlife habitat, some areas of the St. Louis River estuary continue to be at risk from contaminants in the sediment.

Photo by USFWS

In 1962, when Rachel Carson wrote about the impacts of DDT in her landmark book Silent Spring, many people were skeptical of her warning that future years might bring spring without birds’ songs. How could a product that was so widely used be so dangerous? Today, Carson’s counterparts are asking the same question about products that we use every day.

Following in Carson’s footsteps, the Environmental Contaminants program of the U.S. Fish and Wildlife Service is conducting an “early warning” investigation looking at contaminants whose effects are widely used, not well known, and currently unregulated. These substances, called Contaminants of Emerging Concern, tend to be contemporary, but may also include more traditional chemicals (such as some pesticides) that have altered releases or new detections in the environment. Some of these contaminants include hormones and pharmaceuticals, as well as herbicides and pesticides.

Abnormalities have been found on white suckers and other fish from suspected exposure to contaminated sediment.

Photo by USFWS

In the study, biologists are seeking to determine the concentration of these chemicals in the environment, and then find out if those concentrations are harming fish and wildlife. A large number of these chemicals affect the endocrine system and cause effects at very low concentrations. The ultimate goal of this study: prevent the equivalent of another "silent spring" by evaluating and addressing possible impacts on fish and wildlife before they have a major effect on populations, the way DDT affected bird populations.

Because of the work that Rachel Carson and others accomplished, we also now have the capability to help clean up and protect fish and wildlife from existing chemical pollution in the St. Louis River - where more than 100 years of industrialization brought many chemical pollutants to the waterway before environmental regulations were in place. The St. Louis River is the largest U.S. tributary to Lake Superior. While the river serves as a major port in the Great Lakes, the lower 21 miles consists of a 12,000-acre estuary that remains the most significant source of biological productivity for western Lake Superior. It provides important wetland, sand beach, forested and aquatic habitat types for a wide variety of fish and wildlife communities.

Sediment contamination at the Interlake Superfund Site degraded fish and wildlife habitat, and limited recreational use.

Photo by USFWS

The lower portion of the St. Louis River and surrounding watershed was designated by a United States-Canadian Water Quality Agreement as an Area of Concern in 1989 because it is a location that has experienced environmental degradation, including the presence of chemical contaminants, poor water quality, reduced fish and wildlife populations, and habitat loss. The U.S. Fish and Wildlife Service’s Environmental Contaminants program at the Twin Cities Ecological Services Field Office has been an active partner within the lower St. Louis River conservation community for more than 13 years, assisting with contaminated sediment remediation, chemical effects investigations, as well as a variety of other fish and wildlife habitat projects.

For example, the Environmental Contaminants program acted as advisor to help with the clean-up of sediments contaminated with polycyclic aromatic hydrocarbons, called PAHs, and metals at the St. Louis River/Interlake/Duluth Tar Superfund site so that the contaminants no longer pose a threat to fish and wildlife. The Service continues to work with partners on a natural resource damage assessment to restore habitat impacted at the site. Through the Natural Resource Damage Assessment and Restoration Program, co-trustees, like the Service, states and other stakeholders, are able to negotiate with responsible parties to recover and restore the natural resources that the public has lost because of these contaminants.

Biologists collect sediment samples to classify current contaminant levels in the St. Louis River.

Photo by USFWS

In other areas where there are no responsible parties, the Environmental Contaminants program works with local partners to develop and implement Remediation to Restoration, called “R to R” projects. Through R to R projects, partners coordinate efforts to remediate contaminated sediments with actions that restore habitat, providing for a more efficient use of time and money. Sediment in the R to R project areas is known to be contaminated with chemicals, such as PAHs and mercury, which limit the quality of fish and wildlife habitat. Environmental Contaminants biologists and partners approach R to R projects with a vision in mind of the end result: an ecologically healthy and productive site. They develop plans for the remediation of contaminated sediment that are most consistent with restoration goals. By using the R to R template, chemically contaminated sediments will be cleaned up and returned to healthy fish and wildlife habitat for the public to enjoy.

Through these projects and investigations, the Service’s Environmental Contaminants program and other local partners are removing existing chemical threats and working to prevent additional chemical threats to fish and wildlife resources in the St. Louis River; all for the benefit of the public and local stakeholders and partners.